Satellite digital audio radio service (SDARS), a satellite broadcast service established by the U.S. Federal Communications Commission (FCC), has been proposed using satellite transmission of digital audio programs to radio receivers. The radio receivers can be stationary receivers (i.e., with a receiver antenna pointed for optimal line of sight (LOS) reception from a satellite) or mobile receivers (e.g., a receiver that is hand-carried by a user or is mounted in a vehicle).
The type of content which can be distributed in an SDARS system or a similar digital broadcast system typical includes audio programs such as music recordings, news programs and talk shows, among other programs, and advertisements. A digital broadcast also typically comprises dialogue segments from a broadcast channel host or other program host which occur between the audio programs and advertisements presented on a broadcast channel.
A significant amount of the content that is to be broadcast is predetermined prior to transmission such as popular songs. Radio stations, for example, frequently use play lists to determine how often a selected number of songs, which are identified as being most popular at a given point in time, are to be broadcast. Popular songs and other programs which can be repeated on a broadcast channel are in contrast to “live” commentary provided by a broadcast channel host, talk show host or other commentator, for example.
Since bandwidth in a digital broadcast system is limited and valuable, efficient use of the bandwidth is desirable. Accordingly, a digital broadcast system is proposed in U.S. patent application Ser. No. 09/695,226, filed concurrently herewith to Marko et al for “Method and Apparatus for Employing Stored Content at Receivers to Improve Efficiency of Broadcast System Bandwidth Use”, which provides for local storage devices at receivers for storing selected content (e.g., audio programs). The receivers are configured to receive a broadcast signal and to generate an output signal for playback via a loudspeaker, for example, using content transmitted in the broadcast signal, or by accessing and retrieving from the local storage device previously stored content segments that were identified in the broadcast signal.
The local storage device can also be used to store content consisting of relatively large files that have been transmitted to the user receiver via the digital broadcast system. The files can provide updated weather reports, maps, software, advertisements and so on. Due to the size of the files, the digital broadcast system partitions a large file and transmits the partitions in respective bursts to the user receivers. As described in U.S. patent application Ser. No. 09/695,228, to Marko et al for “Method and Apparatus for Implementing File Transfers to Receivers in a Digital Broadcast System” and filed concurrently herewith, the partitions are rebroadcast a number of times. The receivers are configured to buffer the partitions and to monitor the reception and buffering of partitions until substantially all of the file has been captured in a memory device. It would be advantageous to have a receiver operable to generate messages to the user that updated content is available from the local storage device for on-demand access. It would also be advantageous to have the ability to transmit content at a relatively low bit rate that can be captured and stored via the local storage device at a receiver for access at a later time.